The present invention relates to a VWAN (Virtual Wide Area Networks, a synonym of VLAN (virtual Local Area Networks) standardized by IEEE802.1Q [Virtual Bridged Local Area Networks], and other synonyms are VPN (Virtual Private networks), VMAN (Virtual Metro Area networks)) management system of an apparatus installed within a network, which employs a layer-2 switch (L2SW) etc.
In the field related to the VWAN, PoweredCom, Inc. adopted a system such as “Ethernet (registered trademark) over Ethernet (registered trade mark) (EoE)”, and other companies announced systems for reducing a load of a switch on a large quantity of traffic.
According to the EoE, an ingress edge switch (edge SW) attaches MAC (Media Access Control) addresses of an egress edge switch and of the ingress edge switch itself and a VWAN tag to a frame entering the ingress edge switch itself, and sends this frame to within a core network. The frame attached with the MAC addresses and the VWAN tag is forwarded to within the core network. An advantage of the EoE is that the load on the core switch forwarding the frame across the core network may be reduced.
FIG. 1 is an explanatory diagram of a frame format pursuant to the IEEE802.3. As shown in FIG. 1, the frame has a field for storing the VWAN tag. The VWAN tag has fields, and one of the fields is used to store a VWAN-ID (VLAN-ID). The VWAN-ID is an identifier uniquely representing a VWAN group to which the frame belongs, and involves using any one of values “0” through “4095” as specific values.
FIG. 2 illustrates an example of a system including the wide area Ethernet (registered trademark) network by way of an example of the network system utilizing the VWAN. Respective customer edge domains (customer-sided networks) 1 and 2 are connected to the wide area Ethernet (registered trademark) network 3 (which will hereinafter be simply referred to as the network 3) via edge switches 4 each including a switching function.
Individual end users within the customer edge domains 1 and 2 have VWAN-IDs (X, Y, Z) for dividing the frames of the individual customers within the network 3, wherein the frames are transferred and received only between the end users having the same VWAN-ID.
For instance, an assumption is that the customer (the end user) having the VWAN-ID=X in the customer edge domain 1 transmits a frame to the end user having the same VWAN-ID=X in the customer edge domain 2.
In this case, when the frame is received by the edge switch 4 (an ingress edge switch) on the side of the customer edge domain 1, the frame is attached with MAC addresses of the ingress and egress edge switches 4 and with the VWAN-ID=X and is thus sent to within the network 3.
The frame is forwarded to between the core switches (core SWs) in the network 3 and reaches the egress edge switch 4. At the egress edge switch 4, the MAC addresses and the VWAN-ID=X attached to the frame are removed, and this frame is sent to the corresponding end user (VWAN-ID=X) in the customer edge domain 2.
FIG. 3 is a diagram showing a configuration of an apparatus included in a layer-2 switch (applicable to an edge switch and a core switch) in the conventional system. FIG. 3 illustrates that the layer-2 switch includes a receiving line interface unit 6 that receives input traffic (frames) from a facing (opposed) apparatus, a transmitting line interface unit 7 that transmits traffic (frames) to the facing apparatus, a layer-2 switch (L2SW) engine 8 that switches the traffic on the layer-2, a memory 11 containing control information of the L2SW engine 8, and a controlling/monitoring unit 10 that is connected to a terminal 5 for an operation of a maintenance operator (which will hereinafter be simply referred to as the terminal 5) via a user interface unit 9 and monitors the information stored in the memory 11.
FIG. 4 is an explanatory diagram of a learning/retrieving method in the L2SW using the MAC learning table included in the L2SW engine 8. In FIG. 4, when the receiving line interface unit (receiving I/F) 6 receives a frame and a source MAC address in the frame, a port number of a port which was used to receive the frame, and a VWAN-ID in the frame, are stored in the MAC learning table.
Thereafter, if a frame is received from a different port, the MAC learning table is retrieved by use of, as retrieving keys, a destination MAC address (MAC-DA) and the VWAN-ID which are contained in the received frame. At this time, the frame is forwarded to a port (path) that is hit as a result of the retrieving.
In the conventional systems illustrated in FIGS. 3 and 4, the VWAN-ID of the customer-sided network 1 is learned at the edge switch 4 as shown in FIG. 2. It is therefore required that VWAN-IDs corresponding to a learning count (the number of times of learning) and frame receiving ports be managed within the edge switch SW 4. Accordingly, an entry registerable count of the entries (the number of registerable entries) to be contained in the MAC learning table is given such as “the number of MAC Addresses X the number of VWAN-IDs X the number of input (Receiving) ports (symbols “X” are multiplication symbols)”.
Such scheme is required to provide a memory for the MAC learning table having a tremendous quantity of capacity. On the other hand, management of the entries given by “the number of VWAN-IDs X the number of input ports” is required to be conducted. Hence, an output port retrieving process gets complicated, resulting in a possibility that performance of the L2SW is to be deteriorated.
Patent document 1 shown below is given as a document of the prior art related to the present application.
Patent document 1: Japanese Patent Application Laid-Open Publication No. Hei11(1999)-4224